[Analysis of population genetic diversity of mosquitoes from Shandong Province based on mitochondrial DNA cytochrome oxidase subunit I gene fragment].

OBJECTIVE: To explore the characteristics of gene sequence of mtDNA-COⅠ of Culex pipiens pallens from different geographical regions in Shandong Province and different resistant strains from the lab and five common mosquito species, and analyze the genetic diversity of these mosquitoes.

METHODS: Adult mosquitoes were collected from Jinan, Jining, Qingdao cities and other places in Shandong Province. The sensitive, dichlorvos-resistant, pyrethroid-resistant and propoxur-resistant strains were reared in the lab. Five species of mosquito ( Cx. pipiens pallens , Cx. tritaeniorhynchus , Anopheles sinensis , Aedes albopictus , and Armigeres subalbatus ) were collected from Jining City and identified in the lab. mtDNA-COⅠwas specifically amplified by PCR and sequenced. The gene sequences were compared and analyzed by the biological information systems, and the phylogenetic tree was constructed.

RESULTS: The amplified mtDNA-COⅠfragments of Cx. pipiens pallens from eight different cities and four different resistant strains were 528 bp in length, with 67.4% A+T contents and two mutation sites. The nucleotide sequence homology among the different geographic strains was 99.95% and the gene sequences of the four resistant strains were the same, showing a high homogeny. The amplified mtDNA-COⅠfragments of the five species of mosquitoes were 528 bp with 408 conserved sites, 120 variable sites, 42 parsimony informative sites and 78 singleton sites. The A+T contents were between 65.7% and 68.0%. The nucleotide sequence homology among the different mosquito species was between 86.17% and 92.05%, and the molecular identification was consistent with the traditional morphological identification. The molecular phylogenetic study showed that the different species were clustered at their own branch at the species and genus levels, while genera Armigeres was distantly related to the others.

CONCLUSIONS: mtDNA-COⅠcould not serve as the molecular marker to analyze the population genetic variation and phylogenesis of Cx. pipiens pallens from different geographical regions and different resistant strains, but it has species and genus specificities, which could be used for the identification of the mosquito species and genus.